Halo Structure and RR Lyrae Stars in the SDSS-II Supernova Survey

密歇根州立大学的贺拉斯·史密斯博士将在斯隆数字天空调查II超新星探测期间反复覆盖的300平方度的天空中识别天琴座RR恒星。将确定这些天琴座RR恒星的光曲线、金属度，以及在某些情况下的径向速度。这项调查不仅将揭示天琴座RR恒星在迄今尚未完全研究的区域中的整体空间分布，而且还可能识别出与不同合并事件有关的天琴座RR恒星的子集。RR型天琴座恒星是脉动恒星，其进化祖先亲眼目睹了光晕的形成，是极好的标准蜡烛，可以提供对银河系形成的特殊洞察。拟议中的研究将成为密歇根州立大学天体物理学研究生和本科生培训的重要部分。这项研究与密歇根州立大学正在进行的其他变星研究一起，也将为吸引密歇根地区的天文学家参加当地关于变星的会议提供一个焦点。将通过描述这项研究的网页以及在校园天文台开放参观之夜向公众展示来实现更广泛的影响。中学教师将在校园天文台举行的会议上被介绍观察和这项研究，在那里教师将能够获得他们自己的观察。

Dr. Horace Smith, at Michigan State University, will identify RR Lyrae stars within the 300 square degree strip of sky that is being repeatedly covered during the Sloan Digital Sky Survey II supernova survey. Light curves, metallicities, and, in some cases, radial velocities will be determined for these RR Lyrae stars. This survey will not only reveal the overall space distribution of RR Lyrae stars in a hitherto very incompletely studied region of the sky, but it is also likely to identify subsets of RR Lyrae stars associated with distinct merger events. RR Lyrae stars, pulsating stars whose evolutionary progenitors were eyewitnesses to the formation of the halo and which are excellent standard candles, can provide particular insight into the building of the Milky Way.The proposed research will form an important part of the training of both graduate and undergraduate astrophysics students at Michigan State University. This research, together with other variable star studies being carried out at MSU, will also provide a focus for drawing astronomers in the Michigan area to local meetings on variable stars. A wider impact will be achieved through a web page describing the research and also through presentations to the public during open house nights at the campus observatory. Secondary school teachers will be introduced to observing and to this research at sessions held at the campus observatory, where the teachers will be able to obtain observations of their own